Transcriptional control by A-factor of two trypsin genes in Streptomyces griseus
Transcriptional control by A-factor of two trypsin genes in Streptomyces griseus
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DOI：
10.1128/jb.187.1.286-295.2005
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发表时间：
2005-01-01
影响因子：
3.2
通讯作者：
Horinouchi, S
中科院分区：
文献类型：
--
作者：
Kato, JY;Chi, WJ;Horinouchi, S
AdpA是灰色链霉菌A因子调控级联中许多具有不同功能的基因的关键转录激活因子，形成AdpA调节子。胰蛋白酶样活性在野生型菌株的生长后期检测到，但在A因子缺陷型突变体中没有。与这些观察结果相一致的是，在S.发现灰核菌是AdpA调节子的成员; AdpA通过与位于相对于转录起始点约-50个核苷酸位置处的操纵子结合来激活这两个基因的转录。由AdpA诱导的sprT和sprU的转录在孢子形成开始时最活跃。大部分胰蛋白酶活性由S. griseus是由于SprT，因为胰蛋白酶活性在一个SprT破坏突变体大大减少，但在一个SprU破坏突变体只是略有减少。这与sprT mRNA的量远大于sprU转录物的量的观察结果一致。同时破坏sprT和sprU（突变体DeltasprTU），胰蛋白酶活性几乎为零，表明在S.灰色的甚至双突变体DeltasprTU也能正常生长，并在与野生型菌株相同的时间过程中产生气生菌丝和孢子。
AdpA is the key transcriptional activator for a number of genes of various functions in the A-factor regulatory cascade in Streptomyces griseus, forming an AdpA regulon. Trypsin-like activity was detected at a late stage of growth in the wild-type strain but not in an A-factor-deficient mutant. Consistent with these observations, two trypsin genes, sprT and sprU, in S. griseus were found to be members of the AdpA regulon; AdpA activated the transcription of both genes by binding to the operators located at about -50 nucleotide positions with respect to the transcriptional start point. The transcription of sprT and sprU, induced by AdpA, was most active at the onset of sporulation. Most trypsin activity exerted by S. griseus was attributed to SprT, because trypsin activity in an sprT-disrupted mutant was greatly reduced but that in an sprU-disrupted mutant was only slightly reduced. This was consistent with the observation that the amount of the sprT mRNA was much greater than that of the sprU transcript. Disruption of both sprT and sprU (mutant DeltasprTU) reduced trypsin activity to almost zero, indicating that no trypsin genes other than these two were present in S. griseus. Even the double mutant DeltasprTU grew normally and developed aerial hyphae and spores over the same time course as the wild-type strain.